Mulch — Keeping the Moisture In — or Keeping it Out?

It’s a big statement — but I can honestly say that without mulch — I couldn’t garden.

The work involved in gardening without using mulch — not to mention the decrease in productivity — would be beyond my ability to handle. Mulch is a tremendous tool that I would not want to be without!

Like most tools — you have to know how to work with it to get the most out of it.

A reader wrote to me several weeks ago and brought up some things about mulch that sooner or later every gardener has to address and learn to work with in order for their mulch to keep moisture in — rather than keep moisture out.

Sheila wrote:

“I have noticed over the years that some areas that I mulch (with shredded bark) seem to stay dry under the mulch when the rain is not heavy. I know mulch is supposed to help with moisture retention, but I wondered if you have any guidelines on using it correctly so that it doesn’t keep moisture out. Maybe it has to do with the type of mulch you use, but even where I have shredded leaves and pine needles, it seems to do the same. The mulch gets wet on top, but the ground seems to stay dry underneath.”

Key solutions to this problem are

in timing — when you put it on — and

how you apply your mulch.

The best time to apply mulch is after a soaker rain.

A perfect example happened in my garden this winter. Because of some very untypical tree roots (which sooner or later I’ll write about) — 10 of my wonderful garden beds were just about destroyed by digging.

When finally the beds were “put back together” — they were very dry from the soil being exposed to the elements for such a long period of time. I applied only a thin layer of shredded leaves to protect the beds.

I had to wait for 3 rains before we finally got a good soaker that wet the beds down deep and finally allowed me to cover beds and paths with deep layers of straw, leaves or pine tags. The straw, leaves and pine tags were also moist and that was an added bonus. Eventually the moisture in the mulch will move down into the soil.

Had I mulched my beds and paths thickly while they were dry —- they probably would have a little moisture in them by now — but not anywhere near the amount they have because of my chosen strategy. The rain would have seeped through the deep straw but may not have gone as deeply into the bed as is desirable.

Another example takes place almost every summer. By the time my onions come out of the beds in July and August only a skimpy layer of straw remains on the soil. I wait — no matter how long it takes — for a soaker rain and then apply a heavier layer of mulch.

Applying straw, leaves, pine tags, or almost any mulch — be aware of forkfuls that may be matted together. These matted-together-clumps are the main culprits in keeping beds dry — rather than allowing rain to drain through.

Generally speaking, if the mulch you apply is “loose” when you apply it — it’ll better be able to allow rain to penetrate.

There are times that you’ll miss a matted clump of mulch — or one will develop in the process of gardening. When you discover it — just correct the problem.

How to Mulch Lettuce Seedlings

I’m adding this example (March 15, 2013) after receiving an email from a reader who wanted to know how much straw to put on newly planted lettuce seedlings after a rain. (The indication was — that after reading this post — he thought he should mulch the seedlings only after the rain. This will serve as clarification.)

When you transplant lettuce seedlings into the garden — if the soil is the least bit dry — you need to water those seedlings for good root to soil contact. As soon as that’s accomplished sprinkle a thin layer of straw on that area. A light layer that covers the soil all around the seedlings will keep heavy rain from beating down the baby plants. Otherwise you could loose all the lettuce you planted.

Rain will still penetrate through this thin layer of straw, but will protected from damage by heavy rain.

This is a case where you need not apply more straw after the rain —– until the seedlings grow a bit. And then you will continue to add more straw — so that when hot dry weather arrives —- your lettuce will be heavily mulched.

Bark for Mulch

I don’t use bark because it doesn’t make a good mulch. The pieces are big and they naturally overlap each other to keep moisture out.

Wood Chips

Many years ago we had access to two-year-old wood chips. Unlike bark, the chips are small and make a wonderful mulch. I especially liked to use them a foot deep in my paths.

After a year or two we’d dig out the paths. The chips had turned to a wonderful rich soil. We’d throw that on the beds and fill the paths again with wood chips.

And no, it did not take nitrogen away from plants. I think because it was aged enough.

Some say that wood chips can be toxic and that they’re low in nutrients and won’t improve soil fertility. I did NOT find that true with the ones we used —- and we used them for YEARS — at least 10 years. And — as I said — they decayed into a rich soil that our plants loved!

It held water better than anything else. All around – it was the best stuff I’ve ever used!

Final Thoughts

By applying your mulch after a soaker rain, watching for large matted-together-clumps, and using mulch that allows more penetration your mulch will do a better job of keeping moisture in your beds rather than keeping it out.

15 Comments

Hi Theresa,
As you know last year was my first using mulch seriously in the way you describe. I can understand this question, and you gave a great answer. In the beginning of my second year using mulch, I’m having issues with a ton of slugs who have a great habitat in which to live. I’m using Escargo.
When applying the Escargo to new baby plantings, do you sprinkle it under the layer of straw, or over the layer of straw, or in the small ring around the seedling where there is a gap between the straw and the plant?
I’m just beginning to discover the benefits of mulch, millions of earthworms, no watering last year at all, increased productivity of the plants. It’s definitely worth it.

This article was just in time for me. Yesterday I finally found and bought an organic wheat straw and planned to read your older posts about mulching. Good advices about keeping the Moisture in. Thanks. 🙂

It usually depends on the situation, Sandra — but many times — I do all 3 things you asked about.

If I’m not having much of a problem — I might sprinkle a wide band of escargo around the perimeter of the planting.

If I’m having a lot of problem — I’ll sprinkle escargo all around and amongst my seedlings and around the perimeter. They I’ll add a sprinkling of straw. The slugs will go to the escargo in most cases.

Peas can sometimes take a different strategy. When I plant peas I put a thicker layer of mulch than when I transplant lettuce seedlings. As the peas come up through the mulch I continue to add straw. I usually don’t have problem with slugs until the peas are fully grown. Thus — I sprinkle escargo at the base of the peas.
A better strategy might be to put escargo down immediately after I plant. Then add straw. Then add more escargo after they’re fully grown.

There are probably a million ways to approach it. Just use your imagination, try a lot of strategies and do what works best for you.

Hi Theresa…I’ve been using straw for a long time as a mulch and it works great. However, I’ve been reading about Coconut Coir lately and how good it is as a mulch or incorporating it in the soil. Also as a bedding for worm bins. Wondering what you think of it.

Hi Sharon,
I don’t have access to Coconut Coir so have not used it.
I hear and read good things about it — so I would be game for trying it if I could.
Let me know how it does for you if you decide to use it.
Theresa

I’m definitely giving it a lot of thought, Theresa, before I make any investment in coconut coir.
I was reading some very positive comments about it on Amazon.com where it can be ordered and it’s relatively inexpensive. I’ve also heard it’s a good substitute for peat moss. All I know is that it’s made from coconut shells.
I could probably find some at a nursery near me, but like you, I’m hesitant to go in that direction.
I’m totally in agreement with you on marketing stratagies used and appreciate your thoughts on it.
If I do decide to check it out in a small area of my garden, I’ll let you know the results.

This is my third year veggie gardening and the first that I have used straw for mulch. Except for the stray seed that germinates every now and again (which is quite easy just to pluck out), it has by far been the most wonderful thing I’ve yet to use in my garden. I started it a few years ago knowing absolutely nothing about growing food, and had a difficult time (and still do) sticking to my determination to organically garden. I live in a very small town and have access only to Lowes and Walmart, ad I live in an area where I am not allowed to dig the soil (we rent). The first two years I attempted containers for everything, but soon got overwhelmed. This year I constructed two large raised beds. I never knew how little help I would get in coming by non-chemical soil, but I finally did and hauled in bags and bags if leaves and rotting trees from the hills nearby. Luckily, my intuition told me to wait for a heavy rain to soak everything before I mulched, so I got a bale of straw and left it outside to get soaked as well before putting it down. I live in eastern Kentucky and we have very hot humid summers, but so far this year I’ve been amazed at what little watering I’ve had to do. I almost feel neglectful, even though I know I’m not! lol I still don’t know much about keeping my veggies well fed, but I started a compost bin for the first time this year as well and am hoping that, along with all the forest bedding, will be enough to keep them thriving. After everything I’ve read about soil nutrients, I started to wonder if going organic would even work in my situation, and I didn’t get a lot if support in my area; they’re all about miracle gro around here! I’m so happy I found your page, it has certainly helped steady my determination! 🙂 Thank you! (Sorry for such a long comment!)

You comment was WONDERFUL Brittany and I appreciate the time you took to share what you’ve been through!
Sounds like you are doing a fabulous job and are off to a great start. Keep in mind that it is “normal” for 99% of the people to be discouraging to you. They have been totally brainwashed into thinking that chemicals are necessary — but rest assured your can garden organically ANYWHERE and be successful ——and much more successful than with chemicals.

TMG has more than 400 posts to encourage you and help you. And if you run into something that you can’t find in a post feel free to email me (Theresa@TendingMyGarden.com) for help.

Keep your mind set on organic — say little — and don’t listen to the negative talk. Organic works and that’s a fact. I’m living proof and so are many others.

Carol –
You sound like a new reader as well, although I did not see that you had subscribed. In any event – welcome to TMG!

The short answer for wood chips: they basically should be from untreated wood. The more they age the better they are.
I would not use sawdust. But if you do use it, try to make sure it’s been aged a year (or even longer). Be careful and test spots with it just in case.

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